Modeling Complex Interactions of Overlapping River and
Road Networks in a Changing Landscape
NSF Biocomplexity Grant Collaborators: John Loomis 1, Melinda Laituri 1, Jorge A Ramírez 1, Kirk Sherrill 1 and Ellen Wohl 1, Alan Covich 2, Paul Box 3, Todd Crowl 3, and Kaite Hein 3,
Armando González-Cabán 4, Elías Gutíerrez 5, and Luis Santiago 5, and Andy Pike 6, Fred Scatena 6, and Dana Tomlin 6.
Hypothesis:
As road density increases, habitat connectivity decreases. There is an
increase in the number of perturbations in ecological connections that
effect processes such as species migration (shrimp), stream flows, and
disturbance regimes.
Why this study area?
Three river networks in Puerto Rico have similar elevational gradients,
hydrological regimes, steep-headwater channels, drainage areas,
vegetative cover, food-web composition, and seasonally defined
recreational uses. They differ in road densities and access by visitors
via roads. Land uses (urban, rural, and tropical forest) in each of these
three tropical coastal watersheds reflect elevation, with human
developments primarily along the coastal plain.
Colorado State University, 2 University of Georgia, 3 Utah State University, 4 USDA Forest Service,
5 University
of Puerto Rico, and
6 University
of Pennsylvania
Aquatic Biology - Road Network
Geographic Information Systems (GIS)
River-road intersections create visitor access to
streams where aquatic species can be harvested and
water quality can be effected.
Integrative tool for database management and analysis.
Stream Network - Aquatic Biology
Stream communities are a function of elevation, waterfall and
human activities. Arrows show species distribution from mouth
to headwater reaches.
River - Road Nodes
River-Road Crossings within Study Area
60
50
Rio Espiritu Santo
Stream Network
Rio Mameyes
40
Rio Fajardo
30
20
Road Network
10
0
Primary
Secondary
Tertiary
Class 4
Trail
Road Class
Topography
Aquatic Biology - Human Activity
Stream Network - Road Network
Streams are influenced by road effects due to road proximity
and density.
Shrimp species richness and average visitor use of rivers
are inversely related
Habitat
Trophic Aquatic
Migration Biology
Shrimp Species Richness & Average
River Visitor Use
4.5
40
30
20
Hydrology
Geology
Vegetation
4
50
3.5
3
Average River Use
2.5
Shrimp Species
Richness
2
1.5
1
10
0.5
0
0
ES Bridge Sonadora El Verde
New
(2)
Bridge (2) Bridge (2) Jimenez
(3)
Puente Las Vegas
Roto (3)
(2)
Sitename and Road Class
Shrimp Richness
Average River
Visitor Use Hours
60
Stream
Network
Roads within 100m
Stream Buffer
Road Length by Road Class in
Primary
100 m River Buffer
Road Length (m) in River
Buffer
Evaluate the Direct Effects of Roads on River Hydrology and Aquatic Species
Evaluate Indirect Effects of Roads on Water Quality and Aquatic Species from the
Recreation Visitation Roads make possible
Understand Interactions across space, time and themes (Biotic, Physical, Social)
1
Number of River Intersections
Objectives:
The importance of road and river network intersections in determining
dynamic changes to landscapes will be tested using individual/agent-based
simulation modeling that integrates field-based physical, biological and
social sub-models.
Secondary
Tertiary
Class 4
Total Road in Buffer
90000
80000
70000
60000
50000
40000
30000
20000
10000
0
Espiritu Santo
Road Traits
Road
Connectivity
Network
Usage
Human Society Demand
Activity Economic
Demand
Recreation
Mameyes
Fajardo
Roads types in Buffer Watersheds
Class 4
Rio Espiritu Santo
Primary
Rio Fajardo
Secondary
Rio Mameyes
Tertiary
Streams
SWARM: Individual Agent Based Model
100 m Buffer
Human Activity - Stream Network
Road Network - Human Activity
Travel time is an important factor in human activity and
access to recreational river sites.
Higher stream flows may inhibit human activities along
streams.
Sampling Matrix Transcends Scales:
 Recreation: High, Medium, and Low Use
 Road Size: Primary, Secondary, Tertiary, Class 4, and Trail
 Stream Class: Low, Medium, High (Relative Size)
Rio Mameyes River Use versus Stream Flow
Weekend / Holiday
200
45
Total River Use
40
Stream Flow
35
194
184
30
150
125
25
20
100
15
10
50
5
0
0
7/24/2004
7/26/2004
8/1/2004
Stream Flow (CFS)
Identify feed back loops
Recognize Interconnects
across scales
Determine Emergent Properties
Create Education and Outreach
through K-12 partnerships
Visitor and River Use (Hours)
250